The present invention relates in general to the design of a centrifuge rotor which includes a flow shut-off baffle device that is assembled into a rotor subassembly. More specifically, the present invention relates to the design of a tubular baffle ring which press fits into a centertube and is positioned over a fluid inlet port defined in a rotor shaft for controlling the flow of fluid into the centrifuge rotor.
On many small engines, the lube pump is sized for maximum fuel economy, but the result can be dangerously low oil pressure during idle (or low speed) operation, especially if parasitic devices (accessories or a by-pass centrifuge) have been added. Accordingly, many engine manufacturers desire to limit oil flow to parasitic devices, such as a by-pass lube centrifuge, at low oil pressure conditions such as found during engine idle. The objective is to maintain maximum oil pressure to critical engine components such as a turbocharger, valve train, etc.
In the past, this function has been provided by adding a spring-loaded valve plunger to the inlet of the centrifuge. However, this adds significant cost and complexity to the centrifuge housing. This particular approach also adds some restriction to oil flow which causes reduced centrifuge rotor speed. The present invention provides a similar low-pressure cut-off function as part of a centrifuge without adding significant cost to the rotor or housing.
Additionally, there is a desire by customers (centrifuge users) to know or to be informed when a full-rotor condition exists, based on the amount or degree of sludge accumulation. In order to receive or extract the maximum value from the centrifuge rotor, it is important to avoid the premature service or replacement of the rotor. It has been found that the rotor speed does not significantly decrease when the rotor is (fully) loaded with sludge. As such, the speed decrease in the rate of rotor rotation is not large enough to yield a useful indication (of the speed decrease) to the operator. By means of the present invention, the speed of the rotor is caused to be reduced to near zero when the rotor is xe2x80x9cfullxe2x80x9d, thereby providing a simple and cost effective xe2x80x9ccapacity sensorxe2x80x9d in conjunction with the described low-pressure cut off capability.
A centrifuge for separating particular matter from a fluid includes a housing having a base portion defining a fluid inlet, a rotor subassembly assembled into the housing, and including a centertube, a shaft extending through a portion of the centertube, and defining a fluid inlet port and a fluid passageway in flow communication with the fluid inlet. The improvement corresponding to the present invention includes a baffle sleeve assembled into the centertube and positioned so as to cover the fluid inlet port in the shaft while in a first position, the baffle sleeve and the rotor subassembly being movable to a second position where the fluid inlet port of the shaft is uncovered by the baffle sleeve.
One object of the present invention is to provide an improved rotor subassembly for a centrifuge.
Related objects and advantages of the present invention will be apparent from the following description.